Where there is sufficient migrating gas in a production formation to produce liquid from that formation, wells generally incorporate at least one production tubing string connected to suitable well head structure and extending to one or more production formations. A flow bean is typically connected to the well head and establishes a production orifice through which gas and liquid flow from the formation. As the gas flows upwardly through the tubing string, a quantity of liquid is transported with it and is produced at the well head. Liquid will be produced along with the gas, therefore, as long as a relatively high quantity of gas is flowing from the formation into the tubing string.
In the event gas flow within a well is insufficient to cause continuous production of the liquid accumulating within the tubing string, the liquid may in some wells accumulate until the hydrostatic head of the accumulated liquid equals or exceeds the bottom hole pressure of the well, and the well will then become dormant. When this condition develops, the well has been "killed" by accumulation of the liquid produced from the formation. When a well has become killed by accumulated liquid, it will be shut-in by closing the surface valve of the tubing string. Gas from the formation will bubble through the liquid column within the well and will build a head of pressure above the liquid column, serving to drive the liquid column back into the formation, thereby reducing the hydrostatic head of the liquid. As soon as a sufficient volume of liquid has been forced back into the formation by the accumulation of gas above the liquid column, an operation which may take several hours or several days time, the well may be again placed in production service simply by opening the tubing valve. Accumulated liquid within the tubing string downstream of the flow bean will be produced along with the gas flowing from the well until such time as the gas decreases and allows the liquid column to again build sufficiently to overcome the bottom hole pressure and kill the well. The well then must be shut-in by closing the tubing valve and allowing the accumulated gas to again force a substantial volume of the accumulated liquid back into the production formation. To produce a well having insufficient gas flow for continuous production, it is required that the well be periodically be shut-in in the manner described above. This is a very expensive and time consuming procedure because it requires operating personnel to visit the well site periodically to open and close the tubing valve in accordance with the condition of the well. The cost of producing such wells frequently exceeds the commercial production that is obtainable from the wells, and in such case the wells are permanently shut-in. One of the more important problems associated with conventional methods of producing wells of this type results in severe loss of production, and therefore loss of profits of the production operation.
It is desirable to provide means for automatically controlling production of such wells responsive to the condition of the well. It is also desirable to provide means for achieving production from wells, whether the gas for causing production flows from the formation along with the liquid being produced or is injected either at or remote from the well being produced. It is therefore a primary feature of the present invention to provide a novel well production control mechanism that is connected to the tubing string of a well and is responsive to well conditions for achieving production flow of gas and liquid from the well.
It is also a feature of the present invention to provide a novel well production aid and control mechanism that functions to define a liquid accumulation chamber and a gas accumulation chamber within the well and which mechanism is responsive to well conditions for periodic injection of accumulated gas from the gas accumulation chamber into the liquid accumulation chamber for production of accumulated liquid therein.
It is another important feature of the present invention to provide a novel well production control mechanism that functions as a choke device to provide for substantially continuous flow of gas and liquid from the production formation into a liquid accumulation chamber that is in communication with the tubing string of the well.
It is also an important feature of the present invention to provide a novel method of producing liquid from wells, which method includes simultaneous accumulation of liquid and gas within respective liquid and gas accumulation chambers, and, upon accumulation of a predetermined volume of liquid within the liquid accumulation chamber, automatically causes injection of gas from the gas accumulation chamber into the liquid accumulation chamber to cause production of at least part of the liquid that has accumulated within the liquid accumulation chamber.
It is an even further feature of the present invention to provide a novel method of producing liquid from wells having insufficient gas pressure for continuous production thereof without a production aid mechanism, which method results in conservation of gas in the production formation, thereby allowing a greater volume of liquid to be produced than would ordinarily be attainable through conventional production methods.
It is also an important feature of the present invention to provide a novel method of achieving production from a production formation having insufficient pressure for production thereof, wherein such method is accomplished by continuous flow of gas with such flow being varied intermittently in accordance with the condition of the production formation, as desired.
Other and further features, advantages and objects of the present invention will become apparent to one skilled in the art upon consideration of the present disclosure. The form of the invention which will now be described in detail illustrates the general principles of the invention, but it is to be understood that this detailed description is not to be taken as limiting the scope of the present invention.